Jagoan Matematika: Squaring numbers in the hundreds

Jagoan Matematika

Gateway For Tour Brain Math

Sunday, May 20, 2007

Squaring numbers in the hundreds

1. Choose a number over 100 (keep it low for practice,then go higher when expert).
2. The last two places will be the square of the last two digits (keep any carry) _ _ _ X X.
3. The first three places will be the number plus the last two digits plus any carry: X X X _ _.

Example:

1. If the number to be squared is 106:
2. Square the last two digits (no carry): 6 × 6 = 36: _ _ _ 3 6
3. Add the last two digits (06) to the number: 106 + 6 = 112: 1 1 2 _ _
4. So 106 × 106 = 11236.

See the pattern?
1. If the number to be squared is 112:
2. Square the last two digits (keep carry 1): 12 × 12 = 144: _ _ _ 4 4
3. Add the last two digits (12) plus the carry (1) to the number: 112 + 12 + 1 = 125: 1 2 5 _ _
4. So 112 × 112 = 12544.

With a little practice your only limit will be your ability to square the last two digits!

posted by marhadi @ 6:53 AM

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